Acromion
The acromion is a bony projection of the scapula (shoulder blade) that forms the highest point of the shoulder. It extends laterally from the scapular spine and joins the clavicle to form the acromioclavicular (AC) joint. The acromion also forms the roof of the shoulder joint and helps protect the structures beneath it, including the rotator cuff tendons.
Why is it Important?
The acromion plays an essential role in shoulder stability and movement. Its shape influences the space available for the rotator cuff tendons during arm elevation. Variations in acromion shape or abnormal bone growth may reduce this space, increasing the risk of shoulder impingement syndrome and rotator cuff disorders. Understanding its anatomy helps clinicians evaluate shoulder pain more accurately.
Acromion in Physiotherapy
Physiotherapists assess the acromion while examining patients with shoulder pain, reduced range of motion, or suspected AC joint injuries. Palpating the acromion helps identify anatomical landmarks during physical examination. Rehabilitation focuses on improving shoulder mechanics, strengthening the rotator cuff and scapular muscles, and restoring pain-free movement.
Everyday Examples
The acromion supports normal shoulder function during activities such as:
- Reaching overhead
- Combing your hair
- Lifting objects onto a shelf
- Throwing a ball
- Putting on a shirt
Healthy movement around the acromion allows these activities to be performed comfortably.
Quick Facts
| Feature | Details |
|---|---|
| Category | Anatomy |
| Location | Scapula (Shoulder Blade) |
| Forms Joint With | Clavicle |
| Joint Name | Acromioclavicular (AC) Joint |
| Primary Function | Protects the shoulder joint and supports shoulder movement |
| Clinical Relevance | Shoulder impingement, AC joint injuries |
Clinical Pearl
A hooked Type III acromion has been associated with a higher likelihood of rotator cuff impingement. However, shoulder pain results from multiple factors, so clinicians should always combine imaging findings with a thorough clinical examination rather than relying on acromion shape alone.
Frequently Asked Questions
Where is the acromion located?
The acromion is located at the upper outer part of the scapula and forms the highest point of the shoulder.
What is the function of the acromion?
The acromion protects the shoulder joint, forms the AC joint with the clavicle, and provides attachment sites for important muscles and ligaments.